Ma Luisa Mussons

A CYCLOHEXANE SPACER FOR PHOSPHATE RECEPTORS

Abstract A cyclohexane tricarboxylic acid is shown to be a good spacer for phosphate guests. The combination of 8-aminochromenone-2-carboxamide groups with the cyclohexane spacer leads to a versatile receptor which sets six hydrogen bonds with either phosphonic acids or phosphates. Large association constants are obtained for this receptor in DMSO and methanol when tetraalkylammonium phosphates are used as guests.

Readily available chromenone receptors for carboxylates

Abstract Several carboxylate group receptors able to bind syn and anti electron lone pairs have been prepared making use of an aminochromenone fragment. Symmetric ureas and sulfuryl amides permit the establishment of four linear hydrogen bonds with the carboxylate. The flat geometry of the sulfuryl amides complexes and the higher acidity of their hydrogens yield the best association constants.

Improved receptors for dibutylmalonic acid

Abstract New molecular receptors with a dibenz[c,h]acridine skeleton bearing functional groups complementary to dibutylmalonic acid have been developed.

Lactone receptors with catalytic activity

Abstract Three cleft-type receptors have been prepared that associate 2(5H)-furanone in benzene. These complexes show greater reactivity toward pyrrolidine nucleophilic addition than the furanone itself, probably due to stronger hydrogen bonds in going to the transition state.

Chromenone derivatives as receptors for N-benzoylamino acids

The chromenone derivative 5, easy to synthesize from 2-hydroxyacetophenone 1, has been used to prepare the hosts 7–10 and 12. These combine three hydrogen bonds, π-stacking and chargetransfer interactions for the complexation of N-benzoylamino acids in CDCl3.

Dibutylmalonic acid receptors with decarboxylative activity

Abstract Dibutylmalonic acid receptors have been designed to optimize their catalytic decarboxylative activity in the pressence of isoquinoline. A phosphonamide

Chiral receptor for N-benzyloxycarbonyl aminoacid derivatives

Abstract Chiral cleft-type receptors for N-benzyloxycarbonyl aminoacid derivatives have been prepared. Discrimination between aminoacids with non-polar side chains is modest. Better chiral recognition is obtained with serine. A receptor with an aminopyridine unit allows a high association constant with aspartic acid.

Receptors for carboxylates derived from 2-furoic and fusaric acids

Abstract New cleft type hydrogen bonding receptors have been prepared with a view to complexing carboxylates derived from 2-furoic and fusaric acids. An H-bond between these hosts and the heteroatom in the ring of the guest has been established.

Synthesis of the 3-hydroxy oxiracetam enantiomers, potential nootropic drugs

Abstract The enantioselective synthesis of the potentially nootropic compounds 3–6 is reported. Derivative 3 was obtained from the readily available L-tartaric acid, by reduction of the imide 8 prepared with methyl glycinate. The other derivatives 4–6 were obtained from the dihydroxylactam 11 . Protection of one of the hydroxyl groups and a Mitsunobu reaction or triflate displacement of the other group produces the remaining stereoisomers. Aminoderivatives 25 and 27 were obtained by displacement with sodium azide and reduction.

Cleft type receptors with catalytic activity in amide deuteration

Abstract Cleft type receptors have been prepared with a significant activity in amide deuteration. Charge-transfer and hydrogen bonds seems to be responsible for the catalytic activity.